Put some latex gloves on and spray them with bitter apple, Offer fingers to puppy...
I know it sounds nuts, but my little girl did this terrible when she was a puppy and my young sons were getting mauled.
The gloves and bitter apple worked after the first try for us
Try not to get too frustrated, believe me, this will pass, it is a puppy phase!
You can get a potty pad holder at petsmart or you can try taping the pad down to the floor until he loses interest in tearing it up. Also, he will get better at his aim